This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for The Effect of EXPAREL® on Postsurgical Pain, and the Use of Narcotics (NCT03290196), a na phase 4 study. The primary outcome is VAS Pain Score.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03290196 |
| Phase | Phase 4 |
| Condition | Rotator Cuff Tear |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 13 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Andrews Research & Education Foundation |
| Results posted | Yes |
2. Clinical Question
Population
Patients undergoing outpatient shoulder rotator cuff surgery are the population of interest. The condition listed in the record is rotator cuff tear. Enrollment was 13; the record does not provide further eligibility details or a description of the analyzed population.
Intervention
The study intervention was EXPAREL 1.3 % in 20 ML Injection. The registry describes EXPAREL as a liposome injection of bupivacaine intended for single-dose infiltration into the surgical site. The full intervention protocol, including any additional care or medication rules, is not reported in the registry record.
Comparator
No comparator arm is listed. The study is identified as single-group, and allocation is recorded as not applicable. Although the study purpose refers to pain pumps as an alternative under consideration, the record does not describe a pain-pump group or another control group.
Primary question
The primary endpoint is a patient-reported VAS pain score, with assessments scheduled at 12 hours, 24 hours, 36 hours, and 48 hours. The study description frames the question around postsurgical pain control and narcotic use. However, the record does not give numerical pain results or a reported analysis of narcotic use, so it does not establish how scores changed over time or how they compare with another approach.
This is a descriptive question about outcomes observed after use of the study intervention in a small group, rather than a comparative treatment-effect question. Without a control group, any recorded pain experience would be interpreted in the context of the participants and care in this study; it could not by itself separate an intervention effect from other influences on recovery. The registry lists two secondary outcomes, both ASES shoulder scores—one for the surgical arm and one for the healthy arm—but provides no numerical results for them in the record.
3. Trial Design
This was a Phase 4, single-group study sponsored by Andrews Research & Education Foundation. The intervention was EXPAREL 1.3 % in 20 ML Injection, and enrollment was 13. The study focused on patients undergoing outpatient shoulder rotator cuff surgery. Its registry status is terminated. The recorded study start was 2015-09-03, and the primary completion date was 2016-12-22.
The design does not include a randomized comparison: allocation is recorded as not applicable, masking is listed as none, and the study model is single group. There is no like-for-like control arm in the record. Thus, the design can describe experience in the enrolled group if results are available, but it cannot directly estimate a difference between EXPAREL and pain pumps, another treatment, or usual care.
The stated purpose was to determine whether EXPAREL could be used as a safe alternative to pain pumps while limiting narcotic use and providing postoperative pain control. That wording describes the study's objective, not a finding. The registry record does not provide the comparative design needed to answer an alternative-treatment question, nor does it report numerical results for pain or narcotic use.
The primary measure was mean VAS pain score, with standard deviation specified as the measure of dispersion and assessments planned at 12 hours, 24 hours, 36 hours, and 48 hours. Two secondary measures were ASES scores for the surgical and healthy arms. The registry lists four outcome measures overall, but no analyses are recorded. Details such as the intended analysis populations, follow-up completeness, and the full treatment and outcome assessment procedures are not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | EXPAREL 1.3 % in 20 ML Injection |
|---|---|
| STARTED | 13 |
| COMPLETED | 13 |
| NOT COMPLETED | 0 |
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | EXPAREL 1.3 % in 20 ML Injection |
|---|---|---|
| Participants analysed | 13 | |
| Age, Customized: Age | years | 56.6 (SD 6.4) |
| Sex: Female, Male: Female | Participants | 1 |
| Sex: Female, Male: Male | Participants | 12 |
| Race and Ethnicity Not Collected | Participants | — |
| Region of Enrollment: United States | participants | 13 |
6. Primary Endpoint
The registry lists the primary outcome as VAS Pain Score, measured over 12 hours, 24 hours, 36 hours, 48 hours.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the patient-reported visual analog scale (VAS) pain score. The record describes a numeric pain rating on a scale where 0 = none and 10 = severe. It is intended to capture the participant's perceived pain, rather than an observer's judgment or a laboratory measurement. The scheduled assessments are at 12 hours, 24 hours, 36 hours, and 48 hours after surgery.
Pain scores are useful in clinical research because pain is subjective and the person experiencing it is the most direct source for a rating of its intensity. Repeated measurement can describe how reported pain varies across the listed assessment times. The record specifies that the endpoint is summarized as a mean, with standard deviation. The mean describes the group's average score; the standard deviation describes how spread out individual scores are around that average. These summaries answer different questions and should not be treated as interchangeable.
The record does not report mean VAS values, standard deviations, confidence intervals, or an analysis comparing assessment times. Therefore, the scheduled measurement plan can be described, but the actual pain level or its pattern over time cannot be assessed from the registry record. Nor does the record specify a threshold for a meaningful change in VAS score. The study also names narcotic use in its purpose, but no numeric narcotic-use result is included in the recorded endpoint details.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The most important interpretive feature is the single-group design. A group treated with EXPAREL can be described, but without a comparator there is no direct estimate of how its outcomes differ from outcomes under a pain pump or another approach. Participants' pain after surgery can reflect many influences, including the operation and the broader care context. In an uncontrolled study, those influences cannot be separated from the intervention using a between-group comparison.
The registry lists 13 participants enrolled and identifies the study as terminated. It does not report numerical results for the primary VAS endpoint. Although measurements were scheduled at 12 hours, 24 hours, 36 hours, and 48 hours, there are no recorded means or standard deviations with which to describe the observed scores. The record also lists two ASES secondary outcomes but does not include their numerical results. No analyses are recorded. Consequently, no estimate of the intervention's association with pain, no uncertainty interval, and no statistical test result can be interpreted from this record.
The stated objective includes limiting narcotic use and providing postoperative pain control. These aims should not be mistaken for demonstrated outcomes. Numerical narcotic-use results and an analysis of that outcome are not reported in the registry record. The stated aim of assessing safety likewise does not establish safety: the adverse-event figures describe recorded events in a small, single-group study and do not constitute a comparison of risks.
For the serious adverse event categories, the record reports zero affected participants among 13 at risk, with zero deaths. It also records zero participants affected by other adverse events. These are counts in this study, not proof that an event cannot occur, and there is no control group for a comparative safety interpretation. The record does not specify additional detail about event definitions or ascertainment.
Overall, the record supports a description of the study's purpose, design, planned measures, and recorded adverse-event counts. It does not support a conclusion about the size or direction of a pain outcome, the amount of narcotic use, or a comparative benefit or risk. Those questions require reported outcome data and, for causal comparison, a design with an appropriate comparator.
9. Statistical Methods Explained
What does a mean and standard deviation describe?
The primary outcome is continuous: a numeric VAS score. A mean is a summary of the center of a set of scores. It can make a group's overall level easier to communicate, but it does not show the full distribution. For example, the same mean can arise from scores that are tightly clustered or from scores that vary substantially. The standard deviation describes that variability among scores. It is not the standard error and does not, by itself, quantify the precision of the mean estimate.
A confidence interval is a statistical range used to express uncertainty around an estimated quantity, such as a mean or a difference. In general, a narrower interval indicates greater precision under the assumptions of the method, while a wider interval indicates less precision. No confidence interval for the VAS endpoint is reported in the registry record, so precision of the pain estimate cannot be evaluated. The absence of a reported interval is distinct from an interval that is wide or narrow.
What would repeated pain measurements mean?
The VAS assessments were scheduled at 12 hours, 24 hours, 36 hours, and 48 hours. Repeated measurements can describe pain at multiple times, but scores from the same participant are usually related: a participant's earlier score may be associated with that participant's later score. General statistical methods for repeated observations account for this within-person relationship when estimating trends or comparing times. The registry record does not report which method, if any, was used, and no time-specific numerical scores or analysis are recorded.
It is also important to distinguish a set of time-specific summaries from a change analysis. Reporting a mean at each time would describe the group at each assessment; estimating change would require a defined comparison, such as a change from a specified starting point or a modeled time trend. The record does not state a baseline VAS measurement or a particular change estimand. Therefore, no change calculation or trajectory should be inferred from the scheduled assessment times alone.
Why does the single-group design matter?
With one group, outcome summaries can characterize participants who received the intervention, provided those summaries are reported. They do not estimate what would have happened to the same participants under another treatment. A randomized control group can help balance measured and unmeasured factors on average, while a nonrandomized comparison can be affected by differences between groups. This study has neither a randomized allocation nor a listed comparison arm. The registry record therefore does not support a treatment-versus-control contrast.
Masking is listed as none. In general, masking is intended to reduce the influence of knowledge about treatment on assessment or behavior, depending on who is masked. The record does not describe which outcome assessors or participants, if any, could be masked beyond the listed masking designation. Because the endpoint is self-reported, knowledge of care may be relevant to interpretation, but the record does not allow its effect to be assessed.
How should statistical significance and planning be understood?
A p-value, when reported, describes how compatible data are with a specified statistical model and null hypothesis; it is not the probability that a treatment works or that the null hypothesis is true. Statistical significance also does not establish clinical importance. The registry record reports no analyses and no p-values for the outcomes. No conclusion about statistical significance can therefore be drawn.
The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also states that the effect to detect is a stated fraction of the observed effect. Such assumptions can be used for hypothetical planning calculations, but they do not describe this single-group trial's actual design: there was no equal allocation between two study arms. A planning illustration is not observed power and is not evidence that a result was obtained. Numerical planning outputs are not reported in the registry record, and no sample-size justification for the actual study is reported.
Over-dispersion is a general issue in some statistical models: observed variability can exceed what a model assumes, making conventional standard errors too small and confidence intervals too narrow if the extra variability is ignored. It is not possible to determine from the registry record whether over-dispersion is relevant to an analysis in this study, because no analysis model or outcome estimates are reported. More broadly, a model's assumptions should be evaluated against the type and distribution of the data, but the record does not give enough information to assess such choices.
What can the recorded counts establish?
Counts of participants affected by adverse events are descriptive safety information. A count of zero in the observed group means no affected participant was recorded in that category for the stated denominator; it does not establish that the underlying risk is zero. Estimating and comparing event risks requires careful definitions, complete follow-up, and an appropriate comparison, none of which can be fully assessed from these counts alone. The registry lists no serious adverse-event terms, and it does not provide additional event-level details or an analysis.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists four outcome measures, including the primary VAS pain score and two secondary ASES shoulder scores. The primary VAS endpoint has assessments at 12 hours, 24 hours, 36 hours, and 48 hours. Considering multiple outcomes or multiple assessment times can create a multiplicity issue: the more statistical questions examined, the greater the chance that at least one result appears notable by chance when each is tested separately. General approaches include prespecifying a primary comparison, adjusting the testing procedure, or clearly treating additional analyses as exploratory. The record does not report a multiplicity strategy or a statistical analysis plan.
How missing measurements were handled is not reported in the registry record. For repeated outcomes, missingness can matter because participants with observed scores may differ from those without them. General analysis choices include using only available observations, modeling repeated measurements under stated assumptions, or applying methods designed for missing data. Each approach depends on assumptions; no particular approach can be attributed to this study from the record.
The analysis population is not reported in the registry record. It is therefore unclear which enrolled participants would have been included in each outcome analysis, how withdrawals or incomplete follow-up were handled, or whether any analysis population was defined in advance. The record also does not report interim analyses or a sample-size justification for the trial. No assumptions about these features should be inferred from the study's purpose, enrollment, or termination status.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| EXPAREL 1.3 % in 20 ML Injection | 0 | 13 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| EXPAREL 1.3 % in 20 ML Injection | 0 of 13 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| EXPAREL 1.3 % in 20 ML Injection | 0 of 13 |
The registry records one intervention group, with 13 participants at risk for serious adverse events and 0 affected. For other adverse events, it also records 13 at risk and 0 affected. The death count is 0, and no serious adverse-event terms are listed. These are the event counts recorded for this group; they are not estimates from a comparison with another treatment.
A zero count does not prove that an adverse event is impossible or that the intervention has no risk. It means that no affected participant was recorded in the relevant category among those at risk in this study. In a small study, uncommon events may not appear in the observed participants, and a comparator is needed to assess whether event frequency differs between treatment strategies. The registry record does not give event-level descriptions, detailed ascertainment procedures, or a comparative safety analysis.
The study's objective mentions safety, but the objective is not itself a safety finding. The recorded counts are limited evidence about events in this group and should be read separately from any claim about comparative safety or the likelihood of future events.
12. What the Result Does, and Does Not, Mean
The record establishes that the study examined EXPAREL 1.3 % in 20 ML Injection in a single group of patients undergoing outpatient rotator cuff surgery. It identifies postsurgical VAS pain as the primary outcome, specifies the scale endpoints, and lists four scheduled assessment times. It also lists ASES scores for the surgical and healthy arms as secondary measures. These details describe the research question and planned measurements.
They do not establish the observed level of pain. Numerical VAS means and standard deviations are not reported in the registry record, and no analyses are recorded. The record therefore does not show whether pain scores were higher or lower at any assessment time, how much scores varied, or whether they changed over time. It also does not provide numerical findings for the ASES outcomes or narcotic use.
The single-group design means that even a complete description of outcomes would not demonstrate how those outcomes compare with a pain pump or another care strategy. The study's stated purpose asks whether EXPAREL could serve as an alternative while limiting narcotic use and providing pain control; that purpose should not be treated as a result. A causal comparison requires a suitable comparator and an analysis that addresses the design.
The adverse-event counts report zero participants affected in the serious and other event categories among 13 at risk, and zero deaths. These counts are informative as a description of what was recorded, but do not prove absence of risk or establish comparative safety. The registry record also does not provide the analysis details needed to judge completeness or precision.
In short, the registry record describes a small, terminated study and its planned outcomes, but it does not report the numerical outcome results needed to assess pain, narcotic use, or the ASES measures. It cannot establish that EXPAREL is more effective, less effective, safer, or less safe than another approach.
13. Why This Trial Matters Statistically
This trial matters statistically because its design sharply limits which questions can be answered. The study's purpose invokes an alternative to pain pumps, but the record describes a single group and no comparator. A single-group study can contribute descriptive information, but it cannot directly distinguish outcomes associated with the intervention from outcomes that might have occurred under another approach. Making that distinction is central to comparative-effectiveness questions.
The record also highlights the difference between an outcome plan and outcome evidence. VAS pain was scheduled for measurement at multiple times, but the record does not report the numerical scores or analyses. Without those results, neither the average pain level nor its variability or time pattern can be evaluated. Naming an endpoint and its measurement schedule does not substitute for reporting the data and analysis.
Enrollment was 13, and the registry status is terminated. These registry entries provide context, but they do not explain why the study ended or establish how complete the outcome data are. The reason for termination and the completeness of follow-up are not reported in the registry record. The listed zero adverse-event counts are similarly descriptive: they should not be read as evidence that risk is absent.
For researchers and readers, the key lesson is to keep the estimand—the precise quantity a study aims to estimate—aligned with the design and the reported data. A question about comparative treatment effects requires a comparison, while a question about the experience of one treated group requires complete descriptive results. Here, the stated comparative aim and the recorded single-group design do not align, and the numerical outcome analyses are not reported. Recognizing these boundaries prevents objectives, planned measurements, and event counts from being mistaken for conclusions.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The absence of a comparator is a central limitation for interpreting the study's objective of assessing EXPAREL as an alternative to pain pumps. With a single group, the registry record cannot support a direct estimate of comparative pain control, narcotic use, or safety. Masking is listed as none, and the record does not describe further steps to limit the influence of treatment awareness on subjective pain reporting.
The enrollment was 13. This small study size limits how much can be learned about variability and uncommon adverse events, especially when no numerical outcome estimates or uncertainty intervals are reported. The record does not state a sample-size justification for the actual trial. The planning illustration described in the record is not a report of the trial's design or an observed-power calculation.
Outcome reporting is another limitation: the primary VAS values and analyses are not recorded, and numerical results for the two listed ASES outcomes are also absent. Narcotic-use findings are not reported in the registry record. Follow-up completeness, missing-data handling, analysis populations, and outcome-analysis methods are likewise not reported. These omissions prevent assessment of the amount of available data, the precision of estimates, and the robustness of any findings.
The registry status is terminated, but the reason for termination is not reported in the registry record. No conclusion about the study's conduct or the reason it ended should be inferred from that status alone. The record's adverse-event counts provide limited descriptive information and do not include event-level details or a comparative analysis.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: The Effect of EXPAREL® on Postsurgical Pain, and the Use of Narcotics — NCT03290196.
- Registry record last updated 2025-03-30; status last verified 2024-04.
- Results first posted 2025-03-30.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
NCT03290196 is a Phase 4, single-group study sponsored by Andrews Research & Education Foundation. It examined EXPAREL 1.3 % in 20 ML Injection in patients undergoing outpatient rotator cuff surgery. Enrollment was 13. The registry lists masking as none, allocation as not applicable, and status as terminated. The recorded start date was 2015-09-03, with primary completion on 2016-12-22.
The primary outcome was mean VAS pain score, with standard deviation, scheduled at 12 hours, 24 hours, 36 hours, and 48 hours. ASES scores for the surgical and healthy arms were listed as secondary outcomes. Numerical outcome results and analyses are not reported in the registry record. The adverse-event record lists zero serious-event cases, zero other-event cases, and zero deaths among 13 at risk. No comparator is listed, so the record does not provide a direct comparison with pain pumps or another treatment.